In a very wide variety of applications there is a permanent demand for energy sources of ever increasing performance, having higher energy then primary cells having a liquid cathode of the thionyl chloride type.
Potentially the most advantageous electrochemical couple is the couple lithium/fluorine giving a theoretical potential of about 5.9 volts and a theoretical energy density of more than 5000 Wh/kg. However it is difficult to envisage using fluorine directly because of the major handling problems encountered. Fluorine is gaseous at ambient temperature and under atmospheric pressure and is extremely reactive.
In contrast, it is possible to envisage using fluorine in association with some other element giving compounds that are more easily handled at a temperature close to ambient temperature. This applies when fluorine is associated with a halogen, such as bromine, to obtain a compound that is liquid, such as bromine trifluoride, and which can be used as a catholyte in liquid cathode lithium primary cells.
The problem posed by such cells is that anode discharge is limited by a passivation phenomenon.
An object of the present invention is to mitigate this drawback.